OPPORTUNISTIC NOSOCOMIAL PATHOGENS (HOSPITAL-ACQUIRED INFECTIONS), ETIOLOGY, ROLE, DIAGNOSIS, AND PREVENTION

Opportunistic nosocomial infections, also known as hospital-acquired infections (HAIs), represent a major challenge in modern healthcare systems. These infections are caused by opportunistic microorganisms that normally exist as part of the human microflora or in the hospital environment but become pathogenic when the host immune defenses are weakened. The most common causative agents include bacteria such as Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, and Acinetobacter baumannii, as well as fungi of the genus Candida. Such pathogens are frequently associated with medical procedures, prolonged hospitalization, invasive diagnostic and therapeutic interventions, and the widespread use of antibiotics. Nosocomial infections significantly increase patient morbidity and mortality, prolong hospital stays, and contribute to the development of antimicrobial resistance. Diagnosis is based on clinical manifestations, microbiological cultures, laboratory testing, and modern molecular diagnostic methods. Effective prevention requires strict infection control measures, including proper hand hygiene, sterilization and disinfection of medical equipment, rational antibiotic use, and continuous epidemiological surveillance within healthcare facilities. Understanding the etiology, epidemiology, and mechanisms of opportunistic nosocomial infections is essential for improving diagnostic strategies and implementing effective preventive measures in medical institutions.